1. Field of the Invention
The invention relates to a field decoupling element for use with an implantable line having an elongated line body and a function conductor extending in the longitudinal direction of the line body, acting to implement a medical function of the line. The invention also relates to an implantable line of the aforementioned type as well as an implantable medical device for connection of such an implantable line.
2. Description of the Related Art
Medical implants such as pacemakers and defibrillators often have an electric connection to the interior of a patient's body. Such a connection serves to measure electric signals and/or to stimulate cells in the body. This connection is often embodied as an elongated electrode. At the present time, electric signals are transmitted between the implant and the electrode contacts, such as, but not limited to, tips, rings, HV shock coils and sensors with materials that are good conductors.
If an implant-and-electrode system is exposed to strong interfering fields (EMI, MRI), an unwanted malfunction may occur, specifically heating of parts of the system or electric malfunctions (e.g., resets). The heating may result in damage to body tissue or organs when the heated parts come in direct contact with the tissue. This is the case with the electrode tip in particular.
The cause of the unwanted malfunction is the interaction of the field with the elongated line structure of the electrode. The electrode acts like an antenna, receiving energy from the surrounding fields. This energy on the lines that are used therapeutically can be emitted by the antenna distally to the tissue via the electrode contacts (tip, ring, . . . ) or emitted proximally to the implant.
The same problems also occur with other elongated conductive structures whose proximal end is not necessarily connected to an implant (e.g., catheters, temporary electrodes).